Mattia Internullo

Impact of chronic obstructive pulmonary disease on exercise ventilatory efficiency in heart failure

BACKGROUND Heart failure (HF) and chronic obstructive pulmonary disease (COPD) coexistence increases morbidity and mortality. The intercept of ventilation (VEint) on the VE vs. carbon dioxide production (VCO2) relationship during exercise has been found to vary in proportion with dead space (VD) in HF. Considering that increased VD is the key pathophysiological abnormality in COPD but a secondary finding in HF we hypothesized that a high VEint would be useful in suggesting COPD as HF co-morbidity. Our aim was to assess whether an elevated VEint suggests the presence of COPD in HF. METHODS In a multicenter retrospective study, the VE-VCO2 relationship was analyzed both as slope and intercept in HF (n = 108), HF-COPD (n = 106) and COPD (n = 95). Patients with pulmonary arterial hypertension (PAH) (n = 85) and healthy subjects (HF) (n = 56) served as positive and negative controls relative to VE-VCO2 abnormalities, respectively. RESULTS Slope and VEint varied in opposite directions in all groups (p < 0.05) being VE-VCO2 slope highest and lowest in PAH and healthy subjects, respectively. No slope differences were observed among HF, HF-COPD and COPD (32 ± 7, 31 ± 7, and 31 ± 6, respectively). VEint was higher in HF-COPD and COPD compared to HF, PAH and controls (4.8 ± 2.4 L/min, 5.9 ± 3.0 L/min, 3.0 ± 2.6L/min, 2.3 ± 3.3 L/min and 3.9 ± 2.5L/min, respectively; p < 0.01). A VEint ≥ 4.07 L/min identified patients with high probability of having COPD or HF-COPD (sensitivity of 71.6% and specificity of 72.0%). CONCLUSION These data provide novel evidence that a high VEint (≥ 4.07 L/min) should be valued to suggest coexistent COPD in HF patients.

Relationship between daily physical activity and aerobic fitness in adults with cystic fibrosis.

BackgroundThe best clinical practice to investigate aerobic fitness includes measurements obtained during cardiopulmonary exercise testing (CPET), however it remains an underutilised clinical measure in cystic fibrosis (CF). To investigate this further, different methods of quantifying exercise capacity in CF are required. The possibility that measuring physical activity (PA) by a portable accelerometer could be used to assess the CF aerobic state and could be added among the CPET surrogates has not been investigated. The aim of this study was to examine the relationship between PA and exercise fitness both at submaximal and maximal levels in clinically stable adults with CF.MethodsThirty CF patients (FEV1 71 ± 19% predicted) and fifteen healthy controls undertook an incremental CPET on a cycle ergometer. CPET-related measurements included: oxygen uptake (V’O2), carbon dioxide production (V’CO2), ventilatory profile, heart rate (HR) and oxygen pulse (V’O2/HR) throughout exercise and at lactic threshold (LT) and peak. LT measures represent submaximal exercise related data. PA was assessed using the accelerometer SenseWear Pro3 Armband.ResultsModerate (>4.8 metabolic equivalents (METS)) and moderate + vigorous (>7.2 METS) PA was related to V’O2 (p = 0.005 and p = 0.009, respectively) and work rate (p = 0.004 and p = 0.002, respectively) at LT. Moderate PA or greater was positively related to peak V’O2 (p = 0.005 and p = 0.003, respectively). Daily PA levels were similar in CF and healthy controls. Except for peak values, V’O2 profile and the V’O2 at LT were comparable between CF and healthy controls.ConclusionsIn adult CF patients daily PA positively correlated with aerobic capacity. PA measurements are a valuable tool in the assessment of exercise performance in an adult CF population and could be used for interventional exercise trials to optimize exercise performance and health status. PA levels and parameters obtained at submaximal exercise are similar in CF and in healthy controls.

Minute ventilation and heart rate relationship for estimation of the ventilatory compensation point at high altitude: a pilot study

BackgroundThe ventilatory compensation point (VCP) is an exercise threshold which has been used in the design of training programs in sports medicine and rehabilitation. We recently demonstrated that changes in the slope of the minute ventilation to heart rate relationship (ΔV˙E/ΔHR) can be utilized for estimation of the VCP during incremental exercise at sea level (SL). We hypothesized that in hypoxic conditions, such as high altitude (HA), VCP can be also reliably estimated by ΔV˙E/ΔHR.MethodsAt SL and on immediate ascent to HA (5,050 m), six healthy subjects (42 ± 14 SD years) performed a maximal incremental exercise test on a cycle ergometer; O2 uptake (V˙O2), CO2 output (V˙CO2), V˙E, and HR were measured breath-by-breath. The ΔV˙E/ΔHR method for VCP estimation was compared to the standard method using the ventilatory equivalent for CO2 (V˙E/V˙CO2) and end-tidal PCO2 (PETCO2). The ΔV˙E/ΔHR slope values below (S1) and above (S2) VCP were computed by linear regression analysis.ResultsA significant difference between S1 and S2 was observed, at SL and HA, for both the ΔV˙E/ΔHR and V˙E/V˙CO2 methods for VCP estimation. A good agreement between the two methods (ΔV˙E/ΔHR vs. V˙E/V˙CO2) was found for both environmental conditions; the mean difference ± 2 SD of V˙O2 at VCP (VCP-V˙O2) was −22 ± 112 ml/min at SL and 39 ± 81 ml/min at HA. The VCP-V˙O2 was significantly lower at HA compared to SL; in addition, S1 and S2 mean values were significantly higher at HA compared to SL.ConclusionAt HA, VCP may be reliably estimated by the ΔV˙E/ΔHR method.

A 22-year-old woman with unexplained exertional dyspnoea

A 22-year-old woman was referred to our respiratory outpatient clinic to undergo a cardiopulmonary exercise test (CPET), following presentation with a 2-year history of progressive unexplained exertional dyspnoea (ED). Specifically, she described dyspnoea precipitated by walking or running, which gradually improved with rest. She denied chest pain, cough, asthenia or muscular weakness. Until the age of 20, she practised regular non-competitive physical activity. The patient had at term natural childbirth and normal psychophysical development. Menstrual period, started at the age of 14 years, was regular; no pregnancy, nor miscarriage. She was a lifelong non-smoker with no history of illicit substance use or occupational exposure (university student). Her past history included multinodular euthyroid goitre for which she was prescribed regular levothyroxine (75 μg/100 μg on alternate days). She also reported intermittent gastrointestinal discomfort, which had been ascribed to lactose intolerance for which, however, she was not prescribed a lactose-free diet. Her family history revealed an uncle deceased during childhood for ‘cardiac arrhythmia’. Cardiorespiratory and neurological examination was unremarkable. She was normotensive (blood pressure (BP) 100/60 mm Hg, heart rate (HR) 98 bpm in sinus rhythm), not tachypnoeic (respiratory rate 16 breaths/min) and had preserved oxygen saturation (SatO2 98%). Her body mass index was 19.3. Pulmonary function tests showed normal flow indices (FVC 3.52 L—88% of pred; FEV1 3.35 L—96% of pred; Tiffeneau index FEV1/FVC 0.95) and preserved lung volumes and gas transfer (total lung capacity 3.94 L—90% of pred; diffusing capacity of the lungs for carbon monoxide, 96% of pred). A high-resolution chest tomography showed no sign of lung disease. Cardiological (including rest, stress and Holter ECG, as well as cardiac ultrasounds) and neurological (including electromyography) exams showed no abnormalities. Routine blood tests (cell count, glucose and electrolyte levels, iron and ferritin profile, lipid screening, kidney and liver function), erythrocyte sedimentation rate, C reactive protein and muscular enzyme …